According to one aspect of the invention the improved attachment is applied in road planing machines of the type comprising a rotating cutter drum on which a helical flange or ring is mounted. Tungsten carbide tipped steel teeth are mounted on the flange. When the cutter drum rotates the teeth strip away concrete or asphalt pavement surfaces to a desired depth. The removed concrete may be re-used as a base material and the removed asphalt may be used on secondary roads, reprocessed into a high quality mix or stock piled for use later on.
In known road planing machines the teeth are mounted in tool holders which are attached to the flange by welding. In use high tangential forces are applied on the teeth which means that the teeth will penetrate backwards into the tool holders, thereby damaging the latter. When a tool holder is to be replaced it has to be cut loose, whereupon a new tool holder is secured to the flange by welding. This is a time consuming and, due to the high machine cost, expensive operation.
One object of the invention is to decrease the down-time during replacement of a tool holder. This is attained by mounting the cutting tooth in an adapter and wedgingly securing the adapter to the drum so that the adapter is readily attachable and detachable.
Another object of the invention is to increase the lengths of the replacement intervals of the tool holders. This is attained by using a large wedge surface on the tool holder for taking up the axial forces acting on the tooth, thereby preventing the teeth from penetrating backwards.
According to a general aspect of the invention the improved tool holder including an adapter is applied in earth excavating machines in general, particularly machines for extraction of earth formations such as coal and rock.
The above and other objects of the invention are attained by giving the invention the characterizing features stated in the appended claims.
The invention is described in detail in the following description with reference to the accompanying drawings in which two embodiments are shown by way of example. It is to be understood that these embodiments are only illustrative of the invention and that various modifications thereof may be made within the scope of the claims.